From: jsing <jsing@openbsd.org>
Date: Tue, 31 Jan 2023 05:57:08 +0000 (+0000)
Subject: Provide inline assembly bn_umul_hilo() for alpha/powerpc64/riscv64.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=872b6eb842235e22bfefc40415ca7a7e71e75d65;p=openbsd

Provide inline assembly bn_umul_hilo() for alpha/powerpc64/riscv64.

These should work, but are currently untested and disabled.

ok tb@
---

diff --git a/lib/libcrypto/bn/arch/alpha/bn_arch.h b/lib/libcrypto/bn/arch/alpha/bn_arch.h
index 136adf0e977..9bc00911ab0 100644
--- a/lib/libcrypto/bn/arch/alpha/bn_arch.h
+++ b/lib/libcrypto/bn/arch/alpha/bn_arch.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bn_arch.h,v 1.1 2023/01/20 10:04:33 jsing Exp $ */
+/*	$OpenBSD: bn_arch.h,v 1.2 2023/01/31 05:57:08 jsing Exp $ */
 /*
  * Copyright (c) 2023 Joel Sing <jsing@openbsd.org>
  *
@@ -20,5 +20,25 @@
 
 #ifndef OPENSSL_NO_ASM
 
+#if 0 /* Needs testing and enabling. */
+#if defined(__GNUC__)
+#define HAVE_BN_UMUL_HILO
+
+static inline void
+bn_umul_hilo(BN_ULONG a, BN_ULONG b, BN_ULONG *out_h, BN_ULONG *out_l)
+{
+	BN_ULONG h, l;
+
+	/* Unsigned multiplication using a umulh/mulq pair. */
+	__asm__ ("umulh %2, %3, %0; mulq %2, %3, %1"
+	    : "=r"(h), "=r"(l)
+	    : "r"(a), "r"(b));
+
+	*out_h = h;
+	*out_l = l;
+}
+#endif /* __GNUC__ */
+#endif
+
 #endif
 #endif
diff --git a/lib/libcrypto/bn/arch/powerpc64/bn_arch.h b/lib/libcrypto/bn/arch/powerpc64/bn_arch.h
index 4d6571f9cb4..1b8bd61138e 100644
--- a/lib/libcrypto/bn/arch/powerpc64/bn_arch.h
+++ b/lib/libcrypto/bn/arch/powerpc64/bn_arch.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bn_arch.h,v 1.1 2023/01/20 10:04:34 jsing Exp $ */
+/*	$OpenBSD: bn_arch.h,v 1.2 2023/01/31 05:57:08 jsing Exp $ */
 /*
  * Copyright (c) 2023 Joel Sing <jsing@openbsd.org>
  *
@@ -20,5 +20,25 @@
 
 #ifndef OPENSSL_NO_ASM
 
+#if 0 /* Needs testing and enabling. */
+#if defined(__GNUC__)
+#define HAVE_BN_UMUL_HILO
+
+static inline void
+bn_umul_hilo(BN_ULONG a, BN_ULONG b, BN_ULONG *out_h, BN_ULONG *out_l)
+{
+	BN_ULONG h, l;
+
+	/* Unsigned multiplication using a mulhdu/mul pair. */
+	__asm__ ("mulhdu %0, %2, %3; mul %1, %2, %3"
+	    : "=r"(h), "=r"(l)
+	    : "r"(a), "r"(b));
+
+	*out_h = h;
+	*out_l = l;
+}
+#endif /* __GNUC__ */
+#endif
+
 #endif
 #endif
diff --git a/lib/libcrypto/bn/arch/riscv64/bn_arch.h b/lib/libcrypto/bn/arch/riscv64/bn_arch.h
index 4d6571f9cb4..1b4267acc01 100644
--- a/lib/libcrypto/bn/arch/riscv64/bn_arch.h
+++ b/lib/libcrypto/bn/arch/riscv64/bn_arch.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bn_arch.h,v 1.1 2023/01/20 10:04:34 jsing Exp $ */
+/*	$OpenBSD: bn_arch.h,v 1.2 2023/01/31 05:57:08 jsing Exp $ */
 /*
  * Copyright (c) 2023 Joel Sing <jsing@openbsd.org>
  *
@@ -20,5 +20,29 @@
 
 #ifndef OPENSSL_NO_ASM
 
+#if 0 /* Needs testing and enabling. */
+#if defined(__GNUC__)
+#define HAVE_BN_UMUL_HILO
+
+static inline void
+bn_umul_hilo(BN_ULONG a, BN_ULONG b, BN_ULONG *out_h, BN_ULONG *out_l)
+{
+	BN_ULONG h, l;
+
+	/*
+	 * Unsigned multiplication using a mulh/mul pair. Note that the order
+	 * of these instructions is important, as they can potentially be fused
+	 * into a single operation.
+	 */
+	__asm__ ("mulh %0, %2, %3; mul %1, %2, %3"
+	    : "=r"(h), "=r"(l)
+	    : "r"(a), "r"(b));
+
+	*out_h = h;
+	*out_l = l;
+}
+#endif /* __GNUC__ */
+#endif
+
 #endif
 #endif